Question

I have something like this:

public bool Function(IEnumerable<MyObject> MyObj)
{
    var context = new ContextDb();
    var MyObjFromContext = context.MyObjects.Where(obj => obj == MyObj) //that does not compile!
}

At commented section, i cannot do obj == MyObj comparison, because obj is a single item, and MyObj is a list of items.

So how can i obtain MyObjFromContext that is equal to MyObj, but comes from context?

Answer 1

You will probably have to query using the primary key:

var ids = MyObj.Select(o => o.Id).ToArray();
var MyObjFromContext = context.MyObjects.Where(obj => ids.Contains(obj.Id)).ToList()

Obviously this code assumes that your object has a “standard” integer primary key named Id